Fluid flow control for water treatment systems

ABSTRACT

Disclosed are devices, systems and methods for operation and control of gravity-fed fluid flows in water and wastewater related systems. The disclosed flow control system uses gravity to provide a flow of a fluid from a fluid source and a motorized flow control device fluidically coupled to the fluid source to control a defined flow rate of the flow by changing a position of an internal volume of the flow control device through which the fluid flows relative to a fixed level of the fluid in the fluid source. The disclosed devices, systems and methods can be used in a wide variety of systems for environmental and low-energy demand applications such as, for example, a wastewater treatment system to control a flow of wastewater in the system.

CROSS-REFERENCE TO RELATED APPLICATIONS

This patent document claims priorities to and benefits of U.S.Provisional Patent Application No. 62/990,257, titled “FLUID FLOWCONTROL DEVICES FOR WATER TREATMENT SYSTEMS” and filed on Mar. 16, 2020.The entire content of the aforementioned patent application isincorporated by reference as part of the disclosure of this patentdocument.

TECHNICAL FIELD

This patent document relates to water and wastewater technology.

BACKGROUND

Fluid flow control devices regulate change in fluidic properties, suchas flow velocity, pressure, density, and temperature, as well as thepattern or type of fluid flow. As such, devices for controlling the flowof fluids are beneficial in a variety of fluidic systems.

SUMMARY

Disclosed is an automated and remote flow control system for operationsand control of gravity-fed fluid flows in water and wastewater relatedsystems. The disclosed flow control system uses gravity to provide theflow and a motorized flow control device to control a defined flow rate.

In some embodiments in accordance with the present technology, a devicefor fluid flow control in wastewater treatment includes a wastewatercontainment tank fluidically couplable to an external fluid inputdevice, such as a wastewater supplying system, and structured to enclosean interior space to contain input fluid, such as pre-treated or rawwastewater, when received from the external fluid input device, thewastewater containment tank comprising a first access opening to theinterior space to allow the input fluid to enter the interior space, anda second access opening to the interior space to allow the input fluidto exit the interior space to an external fluid processing device, suchas a wastewater treatment device to yield a treated water that isoutputted out of an output port of the external fluid processing device;and a flow control system fluidically coupled to the external fluidprocessing device, where the flow control system comprises an enclosurehaving (i) an inflow port, (ii) an outflow port, and (iii) an internalvolume between the inflow port and the outflow port, the inflow portproviding a third access opening to the internal volume to allow a fluidto enter the internal volume, and the outflow port providing a fourthaccess opening to the internal volume to allow the fluid to exit theinternal volume, and an actuator assembly configured to move theenclosure along a vertical direction aligned with the direction ofgravity so as to control a flow of the fluid through and out of the flowcontrol system, wherein the flow control system is configured to controla flow rate of the fluid through the internal volume by changing aposition of the internal volume relative to (1) a position of theexternal fluid processing device and (2) an upper level of the inputfluid in the wastewater containment tank along the vertical direction,wherein a change of the position of the internal volume changes ahydraulic resistance of a path from the wastewater containment tank tothe outflow port of the flow control system through the internal volume.

Example embodiments of the device can include one or more of at leastthe following features. In some embodiments of the device, for example,the wastewater containment tank is fluidically couplable to a wastewatersupply or pretreatment system, and the input fluid contained by thewastewater containment tank includes raw or pre-treated wastewater. Insome embodiments of the device, for example, the wastewater containmenttank of the device is fluidically couplable to a microbial fuel cell(MFC) device, as the external fluid processing device fluidicallycoupled to the flow control system, the MFC device having an input portto allow the exited input fluid to enter the MFC device from thewastewater containment tank, wherein the MFC device is operable tobioelectrochemically process the exited input fluid by concurrentlygenerating electrical energy and digesting matter in the exited inputfluid to yield the treated water that is outputted out of an output portof the MFC device to the flow control system. In some embodiments of thedevice, for example, the enclosure of the flow control system isconfigured in an inverse U-like shape such that the inflow port and theoutflow port are lower in the vertical direction than the interiorvolume. In some embodiments of the device, for example, the actuatorassembly of the flow control system comprises a holding plate coupled tothe enclosure; a shaft coupled to the holding plate and aligned in thevertical direction; and a motor operatively coupled to the shaft tocause the shaft to move so as to drive the holding plate to move in thevertical direction.

In some embodiments in accordance with the present technology, a flowcontroller device for controlling a flow rate of a fluid includes anenclosure having (i) an inflow port, (ii) an outflow port, and (iii) aninternal volume between the inflow port and the outflow port, whereinthe inflow port is configured to allow a fluid to enter the internalvolume, and wherein the outflow port is configured to allow the fluid toexit the internal volume; and an actuator assembly configured to movethe enclosure along a vertical direction aligned with the direction ofgravity so as to control a flow of the fluid through and out of the flowcontroller device, wherein the flow controller device is configured tocontrol a flow rate of the fluid through the internal volume by changinga position of the internal volume along the vertical direction relativeto (1) a position of a receiving tank that provides the fluid to theinflow port of the flow controller device and (2) an upper level of thefluid in a fluid containment tank that supplies the fluid to thereceiving tank, wherein a change of the position of the internal volumechanges a hydraulic resistance of a path from the fluid containment tankto the outflow port of the flow controller through the internal volume.

In some embodiments in accordance with the present technology, a methodof controlling a fluid flow rate includes providing a fluid to a fluidcontainment tank structured to enclose a first interior space to containthe fluid; providing the fluid from the fluid containment tank to areceiving tank fluidically coupled to the fluid containment tank andstructured to enclose a second interior space to contain the fluid; andcontrolling a flow of the fluid through a flow controller fluidicallycoupled to the receiving tank by changing a position of the internalvolume along the vertical direction and relative to (1) a position ofthe receiving tank and (2) the upper level of the fluid in the fluidcontainment tank, wherein a change of the position of the internalvolume adjusts a hydraulic resistance of a path from the fluidcontainment tank to the outflow port of the flow controller through theinternal volume.

Example embodiments of the method can include one or more of at leastthe following features. In some embodiments of the method, for example,the flow controller is configured to increase the flow rate when adistance between the position of the internal volume and the position ofthe receiving tank decreases in the vertical direction and a heightbetween the position of the receiving tank and the upper level of thefluid in the fluid containment tank is held constant in the verticaldirection. In some embodiments of the method, for example, the flowcontroller is configured to decrease the flow rate when a distancebetween the position of the internal volume and the position of thereceiving tank increases in the vertical direction and a height betweenthe position of the receiving tank and the upper level of the fluid inthe fluid containment tank is held constant in the vertical direction.In some embodiments, for example, the method comprises providing thefluid from the flow controller or from the receiving tank to a watercollection system fluidically coupled to the flow controller or to thereceiving tank and configured to store the provided fluid and/or toroute the provided fluid away from the flow controller or from thereceiving tank. In some embodiments, for example, the method comprisesallowing a gas to enter or exit the internal volume of the flowcontroller through a vent port on an outside of the flow controllerleading through a vent conduit to the internal volume. In someembodiments of the method, for example, a rate of providing the fluidinto the fluid containment tank is equal to or greater than a rate ofproviding the fluid from the fluid containment tank to the receivingtank or to the flow controller. In some embodiments of the method, forexample, the controlling the flow of the fluid through the flowcontroller is operated by a motor that is controlled using a systemprogrammable logic controller (PLC). In some embodiments, for example,the method comprises establishing a calibration relationship between achange in a flow rate of a fluid flow through the flow controller and anumber of movements of a moveable component that moves to achieve thechange in the flow rate. In some embodiments, for example, the methodcomprises measuring a flow rate of a fluid flow through the flowcontroller, comparing the measured flow rate with a pre-set flow ratevalue, and changing the flow rate based on the comparison outcome bycontrolling, through a system programmable logic controller, a motor torotate a shaft a number of rotations determined using the calibrationrelationship.

In some embodiments in accordance with the present technology, a systemfor controlling a flow rate of a fluid includes (I) a fluid containmenttank structured to enclose a first interior space to contain the fluid,the fluid containment tank comprising a first access opening to thefirst interior space to allow the fluid to enter the first interiorspace, a second access opening to the first interior space to allow thefluid to exit the first interior space, a third access opening to thefirst interior space to allow the fluid to exit the first interiorspace, and an overflow conduit fluidically coupled to the fluidcontainment tank at the third access opening at a first end of theoverflow conduit, the overflow conduit having a portion extending fromthe first end into the first interior space to a second end of theoverflow conduit wherein the second end of the overflow conduit providesa fourth access opening into a hollow channel within the overflowconduit, the hollow channel spanning to the first end, and wherein theoverflow conduit is configured to control an upper level of the fluidcontained in the fluid containment tank; (II) a receiving tankfluidically coupled to the fluid containment tank and structured toenclose a second interior space to contain the fluid, the receiving tankcomprising a fifth access opening to the second interior space to allowthe fluid to enter the second interior space, and a sixth access openingto the second interior space to allow the fluid to exit the secondinterior space; and (III) a flow controller fluidically coupled to thereceiving tank and comprising an enclosure having (i) an inflow port,(ii) an outflow port, and (iii) an internal volume between the inflowport and the outflow port, wherein the inflow port is configured toallow the fluid to enter the internal volume, and wherein the outflowport is configured to allow the fluid to exit the internal volume, andan actuator assembly configured to move the enclosure along a verticaldirection aligned with the direction of gravity so as to control a flowof the fluid through and out of the flow controller, wherein the flowcontroller is configured to control a flow rate of the fluid through theinternal volume by changing a position of the internal volume relativeto (1) a position of the receiving tank and (2) the upper level of thefluid in the fluid containment tank along the vertical direction,wherein a change of the position of the internal volume changes ahydraulic resistance of a path from the fluid containment tank to theoutflow port of the flow controller through the internal volume.

The disclosed flow control system, method and devices can be used in awide variety of systems for environmental and low-energy demandapplications on a large, medium or small scale. In some aspects, theflow control system is used in a wastewater treatment system to controla flow of pre-treated wastewater and/or treated wastewater. For example,in some implementations, the wastewater treatment system is abioelectrochemical system based on microbial fuel cell devices used forwastewater treatment and concomitant energy generation.

The subject matter described in this patent document can be implementedin specific ways that provide one or more of the following features.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A and 1B show illustrative diagrams of a gravity-based fluid flowcontrol system in accordance with the present technology.

FIG. 2 shows a schematic representation of an example embodiment of afluid containment tank and directions of the fluid flows inside the tankas well as into and out of the tank.

FIGS. 3A and 3B show a front (FIG. 3A) and a side (FIG. 3B) views of anexample embodiment of a flow controller according to the technologydisclosed in the present application.

FIG. 4 shows an illustrative diagram of an example embodiment of abioelectrochemical system for wastewater treatment which uses agravity-based fluid flow control system in accordance with the presenttechnology.

FIG. 5 shows a diagram illustrating an example user interface for a flowcontrol menu of a gravity-based fluid flow control system in accordancewith the present technology.

FIG. 6A shows a diagram of an example embodiment of a method forcontrolling a flow rate of a fluid flow according to the technologydisclosed in the present application.

FIG. 6B shows a flowchart illustrating an example embodiment of aprocess for controlling fluid flow in accordance with the method shownin FIG. 6A.

DETAILED DESCRIPTION

Traditional ways of controlling flow rate of a fluid flowing through aconduit are based on utilization of mechanical elements such as pumps asthe main part of a flow control system. Movable parts of such mechanicalelements are generally in direct contact with the fluid, and the fluidflow is restricted or increased via changing positions or speed of themovable parts. In cases where the fluid contains considerable amounts ofcontamination (e.g., the fluid is wastewater), using movable parts whichare in direct contact with the fluid can lead to corrosion andmalfunction of the flow control system and thus disrupt or completelyblock the fluid flow through the conduit. In addition, available pumpdevices for industrial water and wastewater related systems are designedto conduct fast flow rates (e.g., hundreds and thousands of gallons perhour), are highly energy-intensive, and take up a large physicalfootprint. Conventional pump devices for industrial applications cannotbe applied for slow flow water systems (e.g., <1 gallons per minute)with a small footprint and low energy demand, such as for abioelectrochemical system for wastewater treatment.

Disclosed are systems, devices and methods for providing fluid flowcontrol. In various implementations, the disclosed systems, devices andmethods can control fluid flow by changing a hydraulic resistance of afluid path from a fluid source through a conduit by changing a positionof the conduit along the direction of gravity and relative to theposition of the fluid source. In this manner, the disclosed fluid flowcontrol technology can avoid using flow control pumps or similarelements. Such gravity-based flow control system can be beneficial for avariety of applications including, but not limited to, wastewatertreatment installations.

FIGS. 1A and 1B show illustrative diagrams of an example implementationof a gravity-based fluid flow control system 100 in accordance with thepresent technology. In the example implementation shown in FIGS. 1A and1B, the gravity-propelled flow of a fluid (e.g., an aqueous solutionsuch as pre-treated wastewater and/or treated wastewater in a wastewatertreatment system) is provided by a fluid containment tank (FC tank)positioned above a top of a receiving body, for example, sometimesreferred to as a “receiving tank” or “receiving containment tank” (RCtank), which is supplied with the fluid. The height (h) between a toplevel of the fluid in the fluid containment tank and the top of thereceiving tank determines the hydraulic head pressure applied to thereceiving tank when the receiving tank is fluidically coupled directlyto the fluid containment tank, as shown, for example, in FIG. 1A.

As shown in FIG. 1A, the fluid flows from the fluid containment tankinto the receiving containment tank and further flows through a flowcontroller and is discharged afterwards. The flow controller controls aflow rate of the fluid through and out of the flow controller and,consequently, controls a flow rate of the fluid from the fluidcontainment tank to the receiving tank and/or a flow rate of the fluidout of the receiving tank. Thick lighter gray arrows in FIG. 1A showdirections of the fluid flow.

As illustrated in FIGS. 1A and 1B, the flow controller is installedafter the receiving tank with respect to the fluid flow. Yet, the flowcontroller can be installed before the receiving tank with respect tothe flow of the fluid. In various embodiments of the flow controlsystem, one or more flow controllers also can be installed before thereceiving tank and/or after the receiving tank. Notably, the sameprinciple of flow control described in the present application appliesirrespective of a flow controller position after the receiving tank orbefore the receiving tank.

The flow control principle is based on a fluid flow rate dependence onthe relative difference (d) between the top level of the fluid in thefluid containment tank and a top point of the flow controller bodythrough which the fluid flows, also depending upon the height (h)between the top level of the fluid in the fluid containment tank and thetop of the receiving tank. Preferably, the height (h) is kept constant.The higher the tank fluid level-controller difference d (e.g., when h isconstant), the higher the flow rate is, and vice versa.

For example, if there is no tank fluid level-controller difference(d=0), then no flow through the flow controller occurs (these arehydrostatic conditions). For example, if there is a pressure gradient(e.g., tank fluid level-controller difference d>0), then flow will occurfrom high pressure towards low pressure (e.g., from a higher liquidlevel towards a lower liquid level, which is, in the case shown in FIG.1A, from the fluid containment tank 110 to the receiving tank 130).Also, for example, the greater the pressure gradient or heightdifference (through the same formation material, i.e., the material ofthe tank), the greater the flow rate; and the flow rate of a fluid willbe different through different formation materials even if the samepressure gradient exists.

As shown in the diagrams of FIGS. 1A and 1B, the gravity-based flowcontrol system 100 includes a fluid containment tank 110 that isstructured to enclose a first interior space 119 to contain a fluid suchas, for example, pre-treated wastewater during wastewater processing ina wastewater treatment system. The fluid containment tank 110 includes afirst access opening 112 to the first interior space 119 to allow thefluid to enter the first interior space, and a second access opening 114to the first interior space 119 to allow the fluid to exit the firstinterior space 119. An inflow line 111 is coupled to the fluidcontainment tank 110 at the first access opening 112 and is used toprovide the fluid to the tank 110. An outflow line 113 is coupled to thetank 110 at the second access opening 114 and is used to supply thefluid from the tank 110 to other elements of the system 100.

In some embodiments, the fluid containment tank 110 includes a thirdaccess opening 116 to the first interior space 119 to allow the fluid toexit the first interior space. In such embodiments, for example, thefluid containment tank 110 also includes an overflow line 115 coupled tothe tank 110 at the third access opening 116, where the overflow line115 has a first portion extending from the third access opening 116 intothe first interior space 119 to a first end 117 of the overflow line,and the overflow line has a second portion extending from the accessopening 116 outside the fluid containment tank 110 to a second end 118of the overflow line. In some embodiments, the overflow line 115 isfluidically coupled to the inflow line 111 via a line 120 to provide areturn path back into the tank 110 for the fluid leaving the fluidcontainment tank 110 through the overflow line 115.

The gravity-based flow control system 100 also includes a receiving tank130 which is to be supplied with the fluid and is fluidically coupled tothe fluid containment tank 110. The receiving tank 130 structured toenclose a second interior space 132 to contain the fluid. The receivingtank includes a fifth access opening 131 to the second interior space132 to allow the fluid to enter the second interior space 132, and asixth access opening 133 to the second interior space 132 to allow thefluid to exit the second interior space 132. The receiving tank 130 iscoupled to the fluid containment tank 110 through the outflow line 113,which connects to the fluid containment tank 110 at the second accessopening 114 to the receiving tank 130 at the fifth access opening 131.

The gravity-based flow control system 100 also includes a flowcontroller 150 having an enclosure 151 (not shown in FIGS. 1A and 1B,and shown in an example embodiment in FIGS. 3A-B) and that includes (i)an inflow port 152, (ii) an outflow port 154, and (iii) an internalvolume 153 of the enclosure 151 between the inflow port 152 and theoutflow port 154. The inflow port 152 is configured to allow the fluidto enter the internal volume 153, and the outflow port 154 is configuredto allow the fluid to exit the internal volume 153.

In various embodiments, the flow controller 150 includes an actuatorassembly (not shown in FIGS. 1A and 1B, and shown in an exampleembodiment in FIGS. 3A-B) configured to move the enclosure 151 of theflow controller 150 along a vertical direction 175 aligned with thedirection of gravity so as to control a flow of the fluid through andout of the flow controller 150.

The flow controller 150 controls flow rate of a fluid through theinternal volume 153 of the flow controller by changing a position of theinternal volume 153 relative to (1) a position of the receiving tank 130and (2) an upper level of the fluid in the fluid containment tank 110along the vertical direction 175, where a change of the position of theinternal volume 153 changes a hydraulic resistance of a path from thefluid containment tank 110 to the outflow port 154 of the flowcontroller 150 through the internal volume 153 of the flow controller.

In some embodiments, provided the configuration of the flow rates of thefluid flows to/from the fluid containment tank 110 is as describedabove, the upper level of the fluid in the fluid containment tank 110along the vertical direction 175 is the level of the first end 117 ofthe overflow line 115 in the interior space 119 of the tank 110.

As shown in FIGS. 1A-1B, for example, the path from the fluidcontainment tank 110 to the outflow port 154 of the flow controller 150through the internal volume 153 of the flow controller can go throughthe outflow line 113, the receiving tank 130, and a line 142 fluidicallycoupled between the sixth access opening 133 of the receiving tank andthe inflow port 152 of the flow controller.

FIG. 2 shows a schematic representation of an example embodiment of thefluid containment tank 110 and directions of the fluid flows inside thetank as well as into and out of the tank. As shown in FIG. 2 , theoverflow line 115 has a hollow interior 115X within the interior of theoverflow line, which spans from the first end 117 to the second end 118.As shown in this example, the overflow line includes a fourth accessopening 121 into the hollow channel 115X at the first end 117. Thefourth access opening provides fluid access from the first interiorspace 119 of the fluid containment tank 110 into the inner channel 115Xof the overflow line. Arrows 127 in FIG. 2 show directions of the fluidflow from the interior space 119 of the fluid containment tank 110 intothe inner channel 115X of the overflow line.

In some implementations, a rate of the fluid inflow into the fluidcontainment tank 110 through the inflow line 111 is equal to or greaterthan a rate of the fluid outflow from the fluid containment tank 110through the outflow line 113. In example embodiments including theoverflow line 115, the overflow line 115 can provide a rate of the fluidoutflow from the fluid containment tank 110 which balances a differencebetween the rate of the fluid inflow into the fluid containment tank 110through the inflow line 111 and the rate of the fluid outflow from thefluid containment tank 110 through the outflow line 113. Such aconfiguration of the flow rates of the fluid flows to/from the fluidcontainment tank 110 causes the top level of the fluid in the tank 110to remain at the level of the first end 117 of the overflow line 115 inthe interior space 119 of the tank 110. Consequently, the distance hbetween the top level of the fluid in the fluid containment tank 110 andthe top of the receiving tank 130 remains constant as long as theposition of the first end 117 of the overflow conduit 115 relative tothe top of the receiving tank 130 does not change.

FIGS. 3A and 3B show a front (FIG. 3A) and a side (FIG. 3B) views of anexample embodiment of the flow controller 150 of the system 100. In theexample embodiment, the enclosure 151 of the flow controller 150includes a piping or tubular enclosure. For example, in someembodiments, the actuator assembly of the flow controller 150 includes aholding plate 181 coupled to the example of the enclosure 151; theactuator assembly includes a shaft 182 (shown in FIG. 3B) coupled to theholding plate 181 and aligned in the vertical direction 175; and theactuator assembly includes a motor 183 operatively coupled to the shaft182 to cause the shaft 182 to move so as to drive the holding plate 181to move in the vertical direction 175. The actuator assembly includes acontrol module that includes a data processing unit, comprising one ormore processors, memory and interface unit. In various implementations,the control module is in communication with the motor to control themotor to drive the components of the flow controller 150. In someembodiments, the shaft 182 includes a spinning shaft that rotates aboutan axis aligned in the vertical direction 175. In some embodiments, theactuator assembly is coupled to a post 184 (shown in FIG. 3B) aligned inthe vertical direction 175 and configured to support the actuatorassembly.

In some embodiments of the flow controller 150, the enclosure 151 of theflow controller 150 comprises a vent port configured to allow a gas toenter or exit the internal volume 153, and the flow controller 150comprises a vent conduit 155 coupled to the enclosure 151 at the ventport at a first end of the vent conduit, the vent conduit having aportion extending from the first end along the vertical direction 175 toa second end of the vent conduit, wherein the vent conduit is configuredto route the gas through the vent conduit between the first end of thevent conduit and the second end of the vent conduit into the flowcontroller 150 or out of the flow controller 150.

In some implementations, the flow controller 150 is configured in aninverse U-like shape, such that the inflow port 152 and the outflow port154 are lower in the vertical direction 175 than the interior volume153, as shown in FIG. 3A.

Various materials including plastic, fiberglass or metal pipe can beused to make elements of the flow controller 150.

The gravity-based fluid flow control system 100 can be implemented in avariety of applications for controlling fluid flow in a system. One suchsystem includes a bioelectrochemical system for wastewater treatment.

FIG. 4 shows an illustrative diagram of an example embodiment of abioelectrochemical system for wastewater treatment 400 which uses anexample embodiment of the gravity-based fluid flow control system 100.In this example, the receiving tank 130 is replaced with one or morebioelectrochemical reactors 410 (e.g., microbial fuel cell (MFC)devices) arranged in hydraulic series in one horizontal plane. The fluidflows from the fluid containment tank 110 into a firstbioelectrochemical reactor, then a second reactor and so on until itleaves the bioelectrochemical reactors and flows through the flowcontroller 150. The wastewater level in the fluid containment tank 110is controlled above the level of the bioelectrochemical reactors 410 toprovide the gravity flow control.

Various embodiments of the wastewater treatment system andbioelectrochemical reactors, e.g., including a microbial fuel cell (MFC)device, are described in U.S. Patent Publication No. 2020/0002200A1,which is incorporated by reference as part of this patent disclosure forall purposes.

In some embodiments, a wastewater treatment system includes a wastewaterpretreatment system configured to pre-treat wastewater by removing atleast some solid particles from the wastewater to produce a pre-treatedwastewater. The wastewater treatment system includes a wastewatercontainment tank (e.g., such as fluid containment tank 110 of FIGS. 1Aand 1B), which is fluidically coupled to the wastewater pretreatmentsystem and structured to enclose an interior space (e.g., interior space119 of tank 110) to contain the pre-treated wastewater. The wastewatercontainment tank includes a first access opening to the interior spaceto allow the pre-treated wastewater to enter the interior space, and asecond access opening to the interior space to allow the pre-treatedwastewater to exit the interior space. The wastewater treatment systemincludes a microbial fuel cell device (e.g., such as MFC device 401shown in FIG. 4 ) fluidically coupled to the wastewater containmenttank, the MFC device having an input port to allow the pre-treatedwastewater to enter the MFC device, and the MFC device is operable tobioelectrochemically process the pre-treated wastewater by concurrentlygenerating electrical energy and digesting matter in the pre-treatedwastewater to yield a treated water that is outputted out of an outputport of the MFC device. The wastewater treatment system includes anembodiment of the flow control system 100 fluidically coupled to the MFCdevice, where the flow control system is configured to control a flowrate of the fluid through the internal volume by changing a position ofthe internal volume relative to (1) a position of the MFC device and (2)an upper level of the pre-treated wastewater in the wastewatercontainment tank along the vertical direction, wherein a change of theposition of the internal volume changes a hydraulic resistance of a pathfrom the wastewater containment tank to the outflow port of the flowcontrol system through the internal volume.

In some implementations, adjustment of a position of the enclosure 151of the flow controller 150 in the vertical direction 175 can be donemanually or it can be done remotely and/or in an automated fashion usingthe actuator assembly described above. For example, the operation of themotor 183 of the actuator assembly can be controlled using aprogrammable logic controller (PLC) and a user interface (UI).

FIG. 5 shows a diagram depicting an example flow control menu of agraphical user interface (GUI) that allows performing adjustments of theflow rate of a fluid through the flow controller. The GUI shows a movingsteps control 510 of the Flow Control menu, which controls how manytracked movements of the actuator assembly of the flow controller 150 asit moves the enclosure (e.g., rotations of the spinning shaft 182 in theexample shown in FIGS. 3A-3B to move the holding plate 181 in a givendirection (“up” or “down”) along the vertical direction 175).

A relationship between a change in a flow rate of a fluid through theflow controller 150 and the numeric value entered into the moving stepscontrol 510 can be determined using a flow controller calibrationprocedure. For example, in a bioelectrochemical system for wastewatertreatment composed of twelve reactors in hydraulic series, e.g., asshown in the example of FIG. 4 , which flowing clean water, rotating thespinning shaft 182 with 30 moving steps to move the internal volume 153of the flow controller 150 up or down, changes the flow rate with0.03±0.01 gpm. Calibration is needed for every system and type of liquidflowing through it.

The GUI includes a flow average indicator 520 indicative of ameasurement of an average fluid flow through the flow controller 150. Insome implementations of the flow controller, for example, the flowcontrol can be done automatically. The average flow rate of a fluid (520in FIG. 5 ) through the flow controller 150 or through some otherlocation fluidically coupled to the flow controller (such as, forexample, through the outflow line 113 shown in FIG. 1 ) can be measuredand compared to a flow target indicator (530 in FIG. 5 ). The flowtarget is the desired flow rate for the flow control system 100. Whenthe flow average deviates from the flow target by more than a presetamount, the PLC of the system adjusts the position of the holding plate181 automatically, using a number of moving steps obtained from theresults of the flow controller calibration procedure, to adjust the flowrate until the flow rate is within a pre-determined range from thetarget flow rate value.

FIG. 6A shows a diagram of an example embodiment of a method 600 forcontrolling a flow rate of a fluid. At process 610, the method 600includes providing a fluid to a fluid containment tank. At process 620,the method 600 includes providing the fluid from the fluid containmenttank to a receiving tank. At process 630, the method 600 includescontrolling a flow of the fluid through a flow controller fluidicallycoupled to the receiving tank. In various implementations of the method600, the processes 610-630 can be performed in a sequence or inparallel.

The method 600 can be implemented, for example, using elements andstructures of the flow control system 100 described above. For example,the fluid containment tank of process 610 can be the fluid containmenttank 110 of the flow control system 100, the receiving tank of process620 can be the receiving tank 130 of the flow control system 100, andthe flow controller of process 630 can be the flow controller 150 of theflow control system 100.

In some implementations of the method 600, a rate of providing the fluidinto the fluid containment tank is equal to or greater than a rate ofproviding the fluid from the fluid containment tank to the receivingtank. As describe above in relation to the flow control system 100, suchrelationship between the flow rates allows keeping the highest level ofthe fluid in the fluid containment tank constant such that the flow rateof a fluid flow in the system 100 is controlled by adjusting just aposition of an internal volume of a flow control mechanism fluidicallycoupled to the receiving tank along a vertical direction aligned withthe direction of gravity.

FIG. 6B shows a flow chart of an example embodiment of the process 630of the method 600. At process 631 of the process 630, the process 630includes measuring flow rate of a flow of the fluid through the flowcontroller. At process 632 of the process 630, the process 630 comparingthe measured flow rate value to a target flow rate value. At process 633of the process 630, the process 633 changing a position of an internalvolume of the flow controller along a vertical direction based on aresult of the comparison.

In some implementations, the process 630 can involve using a flowcontroller, which can include an enclosure having (i) an inflow port,(ii) an outflow port, and (iii) an internal volume between the inflowport and the outflow port, where the inflow port is configured to allowthe fluid to enter the internal volume, and the outflow port isconfigured to allow the fluid to exit the internal volume, and where theflow controller includes an actuator assembly configured to move theenclosure along a vertical direction aligned with the direction ofgravity so as to control a flow of the fluid through and out of the flowcontroller.

In some implementations of the process 633, changing a position of theinternal volume of the flow controller along the vertical direction isdone using the actuator assembly, where the actuator assembly caninclude a holding plate coupled to the enclosure of the flow controller;a shaft coupled to the holding plate and aligned in the verticaldirection; and a motor operatively coupled to the shaft to cause theshaft to move so as to drive the holding plate to move in the verticaldirection.

In some implementations of the process 633, operation of the motor ofthe actuator assembly is controlled using a programmable logiccontroller (PLC).

In some implementations of the process 633, the process 633 includesestablishing a calibration relationship between a change in flow rate ofa fluid flow through the flow controller and a number of rotations ofthe spinning shaft required to achieve the change in the flow rate.

In some implementations of the process 633, changing a position of theinternal volume of the flow controller along the vertical directionbased on the comparison outcome includes controlling, through the PLC,the motor to rotate the spinning shaft a number of rotations determinedusing the calibration relationship.

As discussed above with respect to the various embodiments of thedevices, systems, and method for controlling fluid flow, e.g., for watertreatment applications, the fluid flow control can be implemented usingsuch devices, systems, and methods without the requirement of a pump.The disclosed devices, systems, and methods are structured to utilizegravitational forces to sufficiently drive and control the fluid flow,where an actuator device may be employed to move structures of thedisclosed fluid flow control devices and systems, in some embodiments,to manage such fluid drive and flow control. Yet, it is noted, in someembodiments in accordance with the present technology, a pump (e.g.,peristaltic pump [not shown]) may be used for further assistance withthe disclosed fluid flow control devices and systems. While thedisclosed fluid flow control devices and systems are capable of fluidflow control with a degree of accuracy that may be within a range oftenths of g/m flow averages, the use of a pump coupled to the fluid flowcontrol device and system can further improve on accuracy, e.g.,particularly when greater accuracy is needed (e.g., precision in thehundredths, or thousandths) and/or when the flow is for substantiallysmaller volumes of fluid flow.

EXAMPLES

The following examples are illustrative of several embodiments of thepresent technology. Other exemplary embodiments of the presenttechnology may be presented prior to the following listed examples, orafter the following listed examples.

In some embodiments in accordance with the present technology (exampleA1), a system for energy generation and wastewater treatment includes awastewater pretreatment system to pre-treat wastewater by removing atleast some solid particles from the wastewater and produce a pre-treatedwastewater; a wastewater containment tank fluidically coupled to thewastewater pretreatment system and structured to enclose an interiorspace to contain the pre-treated wastewater, the wastewater containmenttank comprising a first access opening to the interior space to allowthe pre-treated wastewater to enter the interior space, and a secondaccess opening to the interior space to allow the pre-treated wastewaterto exit the interior space; a microbial fuel cell (MFC) devicefluidically coupled to the wastewater containment tank, the MFC devicehaving an input port to allow the pre-treated wastewater to enter theMFC device, and the MFC device is operable to bioelectrochemicallyprocess the pre-treated wastewater by concurrently generating electricalenergy and digesting matter in the pre-treated wastewater to yield atreated water that is outputted out of an output port of the MFC device;and a flow control system fluidically coupled to the MFC device, wherethe flow control system comprises an enclosure having (i) an inflowport, (ii) an outflow port, and (iii) an internal volume between theinflow port and the outflow port, the inflow port providing a thirdaccess opening to the internal volume to allow a fluid to enter theinternal volume, and the outflow port providing a fourth access openingto the internal volume to allow the fluid to exit the internal volume,and an actuator assembly configured to move the enclosure along avertical direction aligned with the direction of gravity so as tocontrol a flow of the fluid through and out of the flow control system,wherein the flow control system is configured to control a flow rate ofthe fluid through the internal volume by changing a position of theinternal volume relative to (1) a position of the MFC device and (2) anupper level of the pre-treated wastewater in the wastewater containmenttank along the vertical direction, wherein a change of the position ofthe internal volume changes a hydraulic resistance of a path from thewastewater containment tank to the outflow port of the flow controlsystem through the internal volume.

Example A2 includes the system of example A1 or any of examples A1-A16,wherein the wastewater containment tank comprises: a fifth accessopening to the interior space, and an overflow conduit coupled to thewastewater containment tank at the fifth access opening at a first endof the overflow conduit, the overflow conduit having a portion extendingfrom the first end into the interior space of the wastewater containmenttank to a second end of the overflow conduit, wherein the second end ofthe overflow conduit provides a sixth access opening into a hollowchannel within the overflow conduit, the hollow channel spanning to thefirst end, and wherein the overflow conduit is configured to control theupper level of the pre-treated wastewater contained in the wastewatercontainment tank.

Example A3 includes the system of example A1 or any of examples A1-A16,wherein the second access opening of the wastewater containment tank isfluidically coupled to the input port of the MFC device.

Example A4 includes the system of example A1 or any of examples A1-A16,wherein the inflow port of the flow control system is fluidicallycoupled to the output port of the MFC device.

Example A5 includes the system of example A1 or any of examples A1-A16,wherein the second access opening of the wastewater containment tank isfluidically coupled to the inflow port of the flow control system.

Example A6 includes the system of example A1 or any of examples A1-A16,wherein the outflow port of the flow control system is fluidicallycoupled to the input port of the MFC device.

Example A7 includes the system of example A1 or any of examples A1-A16,wherein the enclosure of the flow control system is configured in aninverse U-like shape such that the inflow port and the outflow port arelower in the vertical direction than the interior volume.

Example A8 includes the system of example A1 or any of examples A1-A16,wherein the actuator assembly comprises: a holding plate coupled to theenclosure; a shaft coupled to the holding plate and aligned in thevertical direction; and a motor operatively coupled to the shaft tocause the shaft to move so as to drive the holding plate to move in thevertical direction.

Example A9 includes the system of example A8 or any of examples A1-A16,wherein the shaft rotates about an axis aligned in the verticaldirection.

Example A10 includes the system of example A1 or any of examples A1-A16,wherein the actuator assembly is coupled to a post aligned in thevertical direction and configured to support the actuator assembly.

Example A11 includes the system of example A1 or any of examples A1-A16,wherein the flow control system is configured to increase the flow ratewhen a distance between the position of the internal volume and theposition of the MFC device decreases in the vertical direction and aheight between the position of the MFC device and the upper level of thepre-treated wastewater in the wastewater containment tank is heldconstant in the vertical direction.

Example A12 includes the system of example A1 or any of examples A1-A16,wherein the flow control system is configured to decrease the flow ratewhen a distance between the position of the internal volume and theposition of the MFC device increases in the vertical direction and aheight between the position of the MFC device and the upper level of thepre-treated wastewater in the wastewater containment tank is heldconstant in the vertical direction.

Example A13 includes the system of example A1 or any of examples A1-A16,comprising a water collection system fluidically coupled to the flowcontrol system or to the MFC device and configured to store the treatedwater and/or route the treated water received by the water collectionsystem from the flow control system or from the MFC device.

Example A14 includes the system of example A1 or any of examples A1-A16,wherein the MFC device comprises a housing and a bioelectrochemicalreactor that is encased within the housing, wherein thebioelectrochemical reactor includes at least one anode arranged betweencathodes of a cathode assembly.

Example A15 includes the system of example A1 or any of examples A1-A16,wherein the flow control system comprises a vent port providing aseventh access opening to the internal volume to allow a gas to enter orexit the internal volume, and a vent conduit fluidically coupled to theflow control system at the vent port at a first end of the vent conduit,the vent conduit having a portion extending from the first end of thevent conduit along the vertical direction to a second end of the ventconduit, wherein the vent conduit is configured to route the gas throughthe vent conduit between the first end of the vent conduit and thesecond end of the vent conduit into the flow control system or out ofthe flow control system.

Example A16 includes the system of example A1 or any of examples A1-A15,wherein the fifth access opening of the wastewater containment tank isfluidically coupled to the first access opening of the wastewatercontainment tank.

In some embodiments in accordance with the present technology (exampleA17), a method of wastewater treatment and energy generation includespretreating a wastewater using a wastewater pretreatment system byremoving at least some of solid particles from the wastewater to producea pre-treated wastewater; providing the pre-treated wastewater from thewastewater pretreatment system to a wastewater containment tankfluidically coupled to the wastewater pretreatment system and structuredto enclose an interior space to contain the pre-treated wastewater, thewastewater containment tank comprising a first access opening to theinterior space to allow the pre-treated wastewater to enter the interiorspace, and a second access opening to the interior space to allow thepre-treated wastewater to exit the interior space; providing thepre-treated wastewater from the wastewater containment tank to amicrobial fuel cell (MFC) device fluidically coupled to the wastewatercontainment tank, the MFC device comprising an input port to allow thepre-treated wastewater to enter the MFC device, and an output port toallow a treated water to exit the MFC device, wherein the MFC device isoperable to bioelectrochemically process the pre-treated wastewater byconcurrently generating electrical energy and digesting matter in thepre-treated wastewater to yield the treated water; and controlling aflow of at least one of the pre-treated wastewater or the treated waterthrough a flow control system fluidically coupled to the MFC device, theflow control system comprising an enclosure having (i) an inflow port,(ii) an outflow port, and (iii) an internal volume between the inflowport and the outflow port, the inflow port providing a third accessopening to the internal volume to allow a fluid to enter the internalvolume, and the outflow port providing a fourth access opening to theinternal volume to allow the fluid to exit the internal volume, and anactuator assembly configured to move the enclosure along a verticaldirection aligned with the direction of gravity so as to control a flowof the fluid through and out of the flow control system, wherein theflow control system is configured to control a flow rate of the fluidthrough the internal volume by changing a position of the internalvolume relative to (1) a position of the MFC device and (2) an upperlevel of the pre-treated wastewater in the wastewater containment tankalong the vertical direction, wherein a change of the position of theinternal volume changes a hydraulic resistance of a path from thewastewater containment tank to the outflow port of the flow controlsystem through the internal volume.

Example A18 includes the method as in example A17 or any of examplesA17-A36, wherein the wastewater containment tank includes a fifth accessopening to the interior space, and an overflow conduit coupled to thewastewater containment tank at the fifth access opening at a first endof the overflow conduit, the overflow conduit having a portion extendingfrom the first end into the interior space of the wastewater containmenttank to a second end of the overflow conduit, wherein the second end ofthe overflow conduit provides a sixth access opening into a hollowchannel within the overflow conduit, the hollow channel spanning to thefirst end, and wherein the overflow conduit is configured to control theupper level of the pre-treated wastewater contained in the wastewatercontainment tank.

Example A19 includes the method as in example A17 or any of examplesA17-A36, wherein the second access opening of the wastewater containmenttank is fluidically coupled to the input port of the MFC device.

Example A20 includes the method as in example A17 or any of examplesA17-A36, wherein the inflow port of the flow control system isfluidically coupled to the output port of the MFC device.

Example A21 includes the method as in example A17 or any of examplesA17-A36, wherein the second access opening of the wastewater containmenttank is fluidically coupled to the inflow port of the flow controlsystem.

Example A22 includes the method as in example A17 or any of examplesA17-A36, wherein the outflow port of the flow control system isfluidically coupled to the input port of the MFC device.

Example A23 includes the method as in example A17 or any of examplesA17-A36, wherein the enclosure of the flow control system is configuredin an inverse U-like shape such that the inflow port and the outflowport are lower in the vertical direction than the interior volume.

Example A24 includes the method as in example A17 or any of examplesA17-A36, wherein the actuator assembly includes a holding plate coupledto the enclosure; a shaft coupled to the holding plate and aligned inthe vertical direction; and a motor operatively coupled to the shaft tocause the shaft to move so as to drive the holding plate to move in thevertical direction.

Example A25 includes the method as in example A24 or any of examplesA17-A36, wherein the shaft rotates about an axis aligned in the verticaldirection.

Example A26 includes the method as in example A17 or any of examplesA17-A36, wherein the actuator assembly is coupled to a post aligned inthe vertical direction and configured to support the actuator assembly.

Example A27 includes the method as in example A17 or any of examplesA17-A36, wherein the flow control system is configured to increase theflow rate when a distance between the position of the internal volumeand the position of the MFC device decreases in the vertical directionand a height between the position of the MFC device and the upper levelof the pre-treated wastewater in the wastewater containment tank is heldconstant in the vertical direction.

Example A28 includes the method as in example A17 or any of examplesA17-A36, wherein the flow control system is configured to decrease theflow rate when a distance between the position of the internal volumeand the position of the MFC device increases in the vertical directionand a height between the position of the MFC device and the upper levelof the pre-treated wastewater in the wastewater containment tank is heldconstant in the vertical direction.

Example A29 includes the method as in example A17 or any of examplesA17-A36, including providing the treated water from the flow controlsystem or from the MFC device to a water collection system fluidicallycoupled to the flow control system or to the MFC device and configuredto store the provided treated water and/or route the provided treatedwater.

Example A30 includes the method as in example A17 or any of examplesA17-A36, wherein the MFC device comprises a housing and abioelectrochemical reactor that is encased within the housing, whereinthe bioelectrochemical reactor includes at least one anode arrangedbetween cathodes of a cathode assembly.

Example A31 includes the method as in example A17 or any of examplesA17-A36, wherein the flow control system comprises a vent port providinga seventh access opening to the internal volume to allow a gas to enteror exit the internal volume, and a vent conduit fluidically coupled tothe flow control system at the vent port at a first end of the ventconduit, the vent conduit having a portion extending from the first endof the vent conduit along the vertical direction to a second end of thevent conduit, wherein the vent conduit is configured to route the gasinto the flow control system or out of the flow control system throughthe vent conduit.

Example A32 includes the method as in example A17 or any of examplesA17-A36, wherein a rate of providing the pre-treated wastewater from thewastewater pretreatment system to the wastewater containment tank isequal to or greater than a rate of providing the pre-treated wastewaterfrom the wastewater containment tank to the MFC device or to the flowcontrol system.

Example A33 includes the method as in example A17 or any of examplesA17-A36, wherein the fifth access opening of the wastewater containmenttank is fluidically coupled to the first access opening of thewastewater containment tank to provide a return path of the pre-treatedwastewater outputted from the wastewater containment tank through theoverflow conduit back into the wastewater containment tank.

Example A34 includes the method as in example A17 or any of examplesA17-A36, wherein operation of the motor is controlled using a systemprogrammable logic controller (PLC).

Example A35 includes the method as in example A17 or any of examplesA17-A36, comprising establishing a calibration relationship between achange in a flow rate of a fluid flow through the flow controller and anumber of rotations of the spinning shaft required to achieve the changein the flow rate.

Example A36 includes the method as in example A17 or any of examplesA17-A35, comprising measuring a flow rate of a fluid flow through theflow controller, comparing the measured flow rate with a pre-set flowrate value, and changing the flow rate based on the comparison outcomeby controlling, through the system programmable logic controller, themotor to rotate the spinning shaft a number of rotations determinedusing the calibration relationship.

In some embodiments in accordance with the present technology (exampleA37), a system for controlling a flow rate of a fluid includes a fluidcontainment tank structured to enclose a first interior space to containthe fluid, the fluid containment tank comprising a first access openingto the first interior space to allow the fluid to enter the firstinterior space, a second access opening to the first interior space toallow the fluid to exit the first interior space, a third access openingto the first interior space to allow the fluid to exit the firstinterior space, and an overflow conduit fluidically coupled to the fluidcontainment tank at the third access opening at a first end of theoverflow conduit, the overflow conduit having a portion extending fromthe first end into the first interior space to a second end of theoverflow conduit wherein the second end of the overflow conduit providesa fourth access opening into a hollow channel within the overflowconduit, the hollow channel spanning to the first end, and wherein theoverflow conduit is configured to control an upper level of the fluidcontained in the fluid containment tank; a receiving tank fluidicallycoupled to the fluid containment tank and structured to enclose a secondinterior space to contain the fluid, the receiving tank comprising afifth access opening to the second interior space to allow the fluid toenter the second interior space, and a sixth access opening to thesecond interior space to allow the fluid to exit the second interiorspace; and a flow controller fluidically coupled to the receiving tankand comprising an enclosure having (i) an inflow port, (ii) an outflowport, and (iii) an internal volume between the inflow port and theoutflow port, wherein the inflow port is configured to allow the fluidto enter the internal volume, and wherein the outflow port is configuredto allow the fluid to exit the internal volume, and an actuator assemblyconfigured to move the enclosure along a vertical direction aligned withthe direction of gravity so as to control a flow of the fluid throughand out of the flow controller, wherein the flow controller isconfigured to control a flow rate of the fluid through the internalvolume by changing a position of the internal volume relative to (1) aposition of the receiving tank and (2) the upper level of the fluid inthe fluid containment tank along the vertical direction, wherein achange of the position of the internal volume changes a hydraulicresistance of a path from the fluid containment tank to the outflow portof the flow controller through the internal volume.

Example A38 includes the system of example A37 or any of examplesA37-A50, wherein the second access opening of the fluid containment tankis fluidically coupled to the fifth access opening of the receivingtank.

Example A39 includes the system of example A37 or any of examplesA37-A50, wherein the inflow port of the flow controller is fluidicallycoupled to the receiving tank at the sixth access opening.

Example A40 includes the system of example A37 or any of examplesA37-A50, wherein the second access opening of the fluid containment tankis fluidically coupled to the inflow port of the flow controller.

Example A41 includes the system of example A37 or any of examplesA37-A50, wherein the outflow port of the flow controller is fluidicallycoupled to the receiving tank at the fifth access opening.

Example A42 includes the system of example A37 or any of examplesA37-A50, wherein the enclosure of the flow controller is configured inan inverse U-like shape such that the inflow port and the outflow portare lower in the vertical direction than the interior volume.

Example A43 includes the system of example A37 or any of examplesA37-A50, wherein the actuator assembly includes a holding plate coupledto the enclosure; a shaft coupled to the holding plate and aligned inthe vertical direction; and a motor operatively coupled to the shaft tocause the shaft to move so as to drive the holding plate to move in thevertical direction.

Example A44 includes the system of example A43 or any of examplesA37-A50, wherein the shaft rotates about an axis aligned in the verticaldirection.

Example A45 includes the system of example A37 or any of examplesA37-A50, wherein the actuator assembly is coupled to a post aligned inthe vertical direction and configured to support the actuator assembly.

Example A46 includes the system of example A37 or any of examplesA37-A50, wherein the flow controller is configured to increase the flowrate when a distance between the position of the internal volume and theposition of the receiving tank decreases in the vertical direction and aheight between the position of the receiving tank and the upper level ofthe fluid in the fluid containment tank is held constant in the verticaldirection.

Example A47 includes the system of example A37 or any of examplesA37-A50, wherein the flow controller is configured to decrease the flowrate when a distance between the position of the internal volume and theposition of the receiving tank increases in the vertical direction and aheight between the position of the receiving tank and the upper level ofthe fluid in the fluid containment tank is held constant in the verticaldirection.

Example A48 includes the system of example A37 or any of examplesA37-A50, including a water collection system fluidically coupled to theflow controller or to the receiving tank and configured to store thefluid received by the water collection system from the flow controlleror from the receiving tank and/or to route the fluid received by thewater collection system from the flow controller or from the receivingtank away from the flow controller or from the receiving tank.

Example A49 includes the system of example A37 or any of examplesA37-A50, wherein the flow controller comprises a vent port configured toallow a gas to enter or exit the internal volume, and a vent conduitcoupled to the flow controller at the vent port at a first end of thevent conduit, the vent conduit having a portion extending from the firstend of the vent conduit along the vertical direction to a second end ofthe vent conduit, wherein the vent conduit is configured to route thegas through the vent conduit between the first end of the vent conduitand the second end of the vent conduit into the flow controller or outof the flow controller.

Example A50 includes the system of example A37 or any of examplesA37-A50, wherein the third access opening of the fluid containment tankis fluidically coupled to the first access opening of the fluidcontainment tank.

In some embodiments in accordance with the present technology (exampleA51), a method of controlling a fluid flow rate includes providing afluid to a fluid containment tank structured to enclose a first interiorspace to contain the fluid; providing the fluid from the fluidcontainment tank to a receiving tank fluidically coupled to the fluidcontainment tank and structured to enclose a second interior space tocontain the fluid; and controlling a flow of the fluid through a flowcontroller fluidically coupled to the receiving tank by changing aposition of the internal volume along the vertical direction andrelative to (1) a position of the receiving tank and (2) the upper levelof the fluid in the fluid containment tank, wherein a change of theposition of the internal volume adjusts a hydraulic resistance of a pathfrom the fluid containment tank to the outflow port of the flowcontroller through the internal volume.

Example A52 includes the method of example A51 or any of examplesA51-A59, wherein the flow controller is configured to increase the flowrate when a distance between the position of the internal volume and theposition of the receiving tank decreases in the vertical direction and aheight between the position of the receiving tank and the upper level ofthe fluid in the fluid containment tank is held constant in the verticaldirection.

Example A53 includes the method of example A51 or any of examplesA51-A59, wherein the flow controller is configured to decrease the flowrate when a distance between the position of the internal volume and theposition of the receiving tank increases in the vertical direction and aheight between the position of the receiving tank and the upper level ofthe fluid in the fluid containment tank is held constant in the verticaldirection.

Example A54 includes the method of example A51 or any of examplesA51-A59, the method comprising providing the fluid from the flowcontroller or from the receiving tank to a water collection systemfluidically coupled to the flow controller or to the receiving tank andconfigured to store the provided fluid and/or to route the providedfluid away from the flow controller or from the receiving tank.

Example A55 includes the method of example A51 or any of examplesA51-A59, the method comprising allowing a gas to enter or exit theinternal volume of the flow controller through a vent port on an outsideof the flow controller leading through a vent conduit to the internalvolume.

Example A56 includes the method of example A51 or any of examplesA51-A59, wherein a rate of providing the fluid into the fluidcontainment tank is equal to or greater than a rate of providing thefluid from the fluid containment tank to the receiving tank or to theflow controller.

Example A57 includes the method of example A51 or any of examplesA51-A59, wherein the controlling the flow of the fluid through the flowcontroller is operated by a motor that is controlled using a systemprogrammable logic controller (PLC).

Example A58 includes the method of example A51 or any of examplesA51-A59, the method comprising establishing a calibration relationshipbetween a change in a flow rate of a fluid flow through the flowcontroller and a number of movements of a moveable component that movesto achieve the change in the flow rate.

Example A59 includes the method of example A51 or any of examplesA51-A58, the method comprising measuring a flow rate of a fluid flowthrough the flow controller, comparing the measured flow rate with apre-set flow rate value, and changing the flow rate based on thecomparison outcome by controlling, through a system programmable logiccontroller, a motor to rotate a shaft a number of rotations determinedusing the calibration relationship.

In some embodiments in accordance with the present technology (exampleA60), a flow controller device for controlling a flow rate of a fluidincludes an enclosure having (i) an inflow port, (ii) an outflow port,and (iii) an internal volume between the inflow port and the outflowport, wherein the inflow port is configured to allow a fluid to enterthe internal volume, and wherein the outflow port is configured to allowthe fluid to exit the internal volume; and an actuator assemblyconfigured to move the enclosure along a vertical direction aligned withthe direction of gravity so as to control a flow of the fluid throughand out of the flow controller device, wherein the flow controllerdevice is configured to control a flow rate of the fluid through theinternal volume by changing a position of the internal volume along thevertical direction relative to (1) a position of a receiving tank thatprovides the fluid to the inflow port of the flow controller device and(2) an upper level of the fluid in a fluid containment tank thatsupplies the fluid to the receiving tank, wherein a change of theposition of the internal volume changes a hydraulic resistance of a pathfrom the fluid containment tank to the outflow port of the flowcontroller through the internal volume.

Example A61 includes the device of example A60, wherein the flowcontroller device is operable as the flow controller in any of thesystems of examples A1-A16 or A37-A50, or in any of the methods ofexamples A17-A36 or A51-A59.

Implementations of the subject matter and the functional operationsdescribed in this patent document can be implemented in various systems,digital electronic circuitry, or in computer software, firmware, orhardware, including the structures disclosed in this specification andtheir structural equivalents, or in combinations of one or more of them.Implementations of the subject matter described in this specificationcan be implemented as one or more computer program products, i.e., oneor more modules of computer program instructions encoded on a tangibleand non-transitory computer readable medium for execution by, or tocontrol the operation of, data processing apparatus. The computerreadable medium can be a machine-readable storage device, amachine-readable storage substrate, a memory device, a composition ofmatter effecting a machine-readable propagated signal, or a combinationof one or more of them. The term “data processing unit” or “dataprocessing apparatus” encompasses all apparatus, devices, and machinesfor processing data, including by way of example a programmableprocessor, a computer, or multiple processors or computers. Theapparatus can include, in addition to hardware, code that creates anexecution environment for the computer program in question, e.g., codethat constitutes processor firmware, a protocol stack, a databasemanagement system, an operating system, or a combination of one or moreof them.

A computer program (also known as a program, software, softwareapplication, script, or code) can be written in any form of programminglanguage, including compiled or interpreted languages, and it can bedeployed in any form, including as a stand-alone program or as a module,component, subroutine, or other unit suitable for use in a computingenvironment. A computer program does not necessarily correspond to afile in a file system. A program can be stored in a portion of a filethat holds other programs or data (e.g., one or more scripts stored in amarkup language document), in a single file dedicated to the program inquestion, or in multiple coordinated files (e.g., files that store oneor more modules, sub programs, or portions of code). A computer programcan be deployed to be executed on one computer or on multiple computersthat are located at one site or distributed across multiple sites andinterconnected by a communication network.

The processes and logic flows described in this specification can beperformed by one or more programmable processors executing one or morecomputer programs to perform functions by operating on input data andgenerating output. The processes and logic flows can also be performedby, and apparatus can also be implemented as, special purpose logiccircuitry, e.g., an FPGA (field programmable gate array) or an ASIC(application specific integrated circuit).

Processors suitable for the execution of a computer program include, byway of example, both general and special purpose microprocessors, andany one or more processors of any kind of digital computer. Generally, aprocessor will receive instructions and data from a read only memory ora random access memory or both. The essential elements of a computer area processor for performing instructions and one or more memory devicesfor storing instructions and data. Generally, a computer will alsoinclude, or be operatively coupled to receive data from or transfer datato, or both, one or more mass storage devices for storing data, e.g.,magnetic, magneto optical disks, or optical disks. However, a computerneed not have such devices. Computer readable media suitable for storingcomputer program instructions and data include all forms of nonvolatilememory, media and memory devices, including by way of examplesemiconductor memory devices, e.g., EPROM, EEPROM, and flash memorydevices. The processor and the memory can be supplemented by, orincorporated in, special purpose logic circuitry.

It is intended that the specification, together with the drawings, beconsidered exemplary only, where exemplary means an example. As usedherein, the singular forms “a”, “an” and “the” are intended to includethe plural forms as well, unless the context clearly indicatesotherwise. Additionally, the use of “or” is intended to include“and/or”, unless the context clearly indicates otherwise.

While this patent document contains many specifics, these should not beconstrued as limitations on the scope of any invention or of what may beclaimed, but rather as descriptions of features that may be specific toparticular embodiments of particular inventions. Certain features thatare described in this patent document in the context of separateembodiments can also be implemented in combination in a singleembodiment. Conversely, various features that are described in thecontext of a single embodiment can also be implemented in multipleembodiments separately or in any suitable subcombination. Moreover,although features may be described above as acting in certaincombinations and even initially claimed as such, one or more featuresfrom a claimed combination can in some cases be excised from thecombination, and the claimed combination may be directed to asubcombination or variation of a subcombination.

Similarly, while operations are depicted in the drawings in a particularorder, this should not be understood as requiring that such operationsbe performed in the particular order shown or in sequential order, orthat all illustrated operations be performed, to achieve desirableresults. Moreover, the separation of various system components in theembodiments described in this patent document should not be understoodas requiring such separation in all embodiments.

Only a few implementations and examples are described and otherimplementations, enhancements and variations can be made based on whatis described and illustrated in this patent document.

What is claimed is:
 1. A method of controlling a fluid flow rate,comprising: providing a fluid to a fluid containment tank structured toenclose a first interior space to contain the fluid; providing the fluidfrom the fluid containment tank to a receiving tank fluidically coupledto the fluid containment tank and structured to enclose a secondinterior space to contain the fluid; and controlling a flow of the fluidthrough a flow controller fluidically coupled to the receiving tank bychanging a position of an internal volume of the flow controller along avertical direction and relative to (1) a position of the receiving tankand (2) an upper level of the fluid in the fluid containment tank,wherein a change of the position of the internal volume adjusts ahydraulic resistance of a path from the fluid containment tank to anoutflow port of the flow controller through the internal volume, whereinthe flow controller is configured to perform one or both of: increasethe flow rate when a distance between the position of the internalvolume of the flow controller and the position of the receiving tankdecreases in the vertical direction and a height between the position ofthe receiving tank and the upper level of the fluid in the fluidcontainment tank is held constant in the vertical direction, decreasethe flow rate when a distance between the position of the internalvolume of the flow controller and the position of the receiving tankincreases in the vertical direction and a height between the position ofthe receiving tank and the upper level of the fluid in the fluidcontainment tank is held constant in the vertical direction.
 2. Themethod of claim 1, comprising: providing the fluid from the flowcontroller or from the receiving tank to a water collection systemfluidically coupled to the flow controller or to the receiving tank andconfigured to store the provided fluid and/or to route the providedfluid away from the flow controller or from the receiving tank.
 3. Themethod of claim 1, comprising: allowing a gas to enter or exit theinternal volume of the flow controller through a vent port on an outsideof the flow controller leading through a vent conduit to the internalvolume.
 4. The method of claim 1, wherein a rate of providing the fluidinto the fluid containment tank is equal to or greater than a rate ofproviding the fluid from the fluid containment tank to the receivingtank or to the flow controller.
 5. The method of claim 1, wherein thecontrolling the flow of the fluid through the flow controller isoperated by a motor that is controlled using a system programmable logiccontroller (PLC).
 6. The method of claim 1, comprising: establishing acalibration relationship between a change in a flow rate of a fluid flowthrough the flow controller and a number of movements of a moveablecomponent of the flow controller that moves to achieve the change in theflow rate.
 7. The method of claim 6, comprising: measuring a flow rateof a fluid flow through the flow controller, comparing the measured flowrate with a pre-set flow rate value, and changing the flow rate based ona comparison of the flow rate with the pre-set flow rate value bycontrolling, through a system programmable logic controller, a motor torotate a shaft a number of rotations determined using the calibrationrelationship.
 8. The method of claim 1, comprising: establishing acalibration relationship between a change in a flow rate of a fluid flowthrough the flow controller and a number of rotation movements of amoveable component of the flow controller that moves the flow controllerup or down in vertical direction onto a threaded shaft to achieve thechange in the flow rate.
 9. The method of claim 1, further comprising:pretreating a wastewater using a wastewater pretreatment system byremoving at least some of solid particles from the wastewater to producea pre-treated wastewater; and providing the pre-treated wastewater fromthe wastewater pretreatment system to the fluid containment tankfluidically coupled to the wastewater pretreatment system.
 10. Themethod of claim 9, wherein the receiving tank includes a microbial fuelcell (MFC) device, wherein the MFC device is operable tobioelectrochemically process the pre-treated wastewater by concurrentlygenerating electrical energy and digesting matter in the pre-treatedwastewater to yield a treated water.
 11. The method of claim 1, whereinthe flow controller is disposed in an enclosure configured in an inverseU-like shape.